Hearing device and method for choosing a program in a multi program hearing device

ABSTRACT

The invention concerns a hearing device having an input transducer and an output transducer with a signal path therebetween, signal processing means connected in said signal path for influencing a signal in the signal path dependent on a PPS (processing parameter set), and a PPS memory accessible by the signal processor means for storing a number of different PPS&#39;s for use by the signal processing means. The system has means for monitoring the acoustic environment in a learning mode, where the user chooses the PPS to be used in the signal processing. Later in an automatic mode the hearing aid system chooses the PPS based on a comparison of the current acoustic environment with the monitored environment in the learning phase.

AREA OF THE INVENTION

The invention is directed to programmable hearing aid systems wherein anumber of different programs are provided and among which the user ofthe hearing aid can choose in order to use the program best suited tothe actual acoustic environment. The invention is useable in connectionwith both in the ear and behind the ear hearing aids as well asimplantable devices with electrical or mechanical stimulation of innerear part.

BACKGROUND OF THE INVENTION

The act of choosing a program can be done discretely by the use of aremote control, or less discretely by touching buttons placed on thehearing aid. In either case however the user is made aware of hishearing disability and in some degree also people around may notice thisaction. Further this action may take some time, and during this time theattention of the haring aid user is directed to the hearing aid and notdirectly at the surroundings, and these moments of less attention isdisturbing to both the hearing aid user and to the people who aremaintaining a conversation or other kind of communication with him orher.

From U.S. Pat. No. 6,035,050 a hearing aid system is known, wherein asolution to the above problem is attempted. The hearing aid system has amatching arrangement with a first memory for several parameter setsavailable for selection for each of several hearing situations, an inputunit for selecting a current hearing situation and for selecting one ofthe several parameter sets available for this hearing situation, and asecond memory for allocation data that identify the parameter setsselected for each hearing situation. For the determination of an optimalparameter set for each of several hearing situations, an optimaluser-specific parameter set is allocated to each hearing situation as itarises during an optimization phase. After the optimization phase, theallocation data are evaluated in order to determine an optimal parameterset for each hearing situation. This parameter set is then programmed asthe parameter set which will be called to set the transmissioncharacteristics of the hearing aid whenever the hearing situationallocated thereto occurs.

According to the teachings of U.S. Pat. No. 6,035,050 the user needs toselect both a hearing situation, which he believes to be in and make achoice as to the processing parameter set, which provides the bestperformance in the given situation. This leaves the user with manycomplex choices during the optimization phase, and the risk of confusionis high. Further this prior art hearing aid system prescribes the use ofboth an auxiliary module and a control module.

SUMMARY OF THE INVENTION

The object of the invention is to provide a hearing aid system with alearning capacity, which is easy and straightforward to use and wherethe training can be carried out without the use of any special devicesapart from the hearing aid and possibly a remote control.

This is achieved according to the invention with a hearing devicecomprising:

-   -   a programmable hearing aid having an input transducer and an        output transducer with a signal path therebetween, and a signal        processing means connected in said signal path for influencing a        signal in the signal path dependent on a Processing Parameter        Set (hereafter named PPS), and a PPS memory accessible by the        signal processor means for storing a number of different PPS's        for use by the signal processing means,    -   user input means for the user to choose a specific PPS to be        used by the signal processing means in a manual mode whenever        the user experiences a specific acoustic environment,    -   means for storing in a second memory of Characterizing Acoustic        Values (hereafter named CAV) derived from the signal during use        of each of the user chosen PPS during a learning period in the        manual mode,    -   means for capturing and temporarily storing in a first memory of        current CAV in an automatic mode,    -   means for automatic selection of a PPS in an automatic mode,        whereby the selection is based on the comparison between current        CAV's stored in the first memory and CAV's stored in the second        memory.

In the following a distinction is made between an acoustic value, and aCharacterizing Acoustic Value (CAV), where an acoustic value as thevalue at one specific point in time of an acoustic parameter, whereasthe CAV is determined on the basis of several acoustic values which arelogged during a period of time.

Each of the PPS's or processing parameter sets are similar to a program,and in the learning period the user only has to find out which of anumber of PPS possibilities gives the best or preferred sound. Thepossible choices of PPS's are preferably programmed into the hearing aidby the hearing aid acoustician based on the users expected needs andlifestyle. Once a PPS is chosen in a given sound environment the hearingaid system starts to record and store the CAV's or characterizingacoustic values of that environment. During the learning period allpossible PPS's should be activated in order for the hearing aid systemto store sufficient data or CAV's for the acoustic environment in whichthe user chooses to activate the respective PPS. Once the learningperiod is over the automatic mode is activated, and now the currentCAV's are continually calculated and compared with the stored CAV's. Thebest match between current and stored CAV's form the basis of anautomatic choice of PPS. When using the hearing aid the user only has tochoose program or PPS's during the learning period, and he does not haveto worry about the sound environment. In the automatic mode the hearingaid is capable of choosing the program or PPS which matches the choicesmade during the training period.

In an embodiment of the invention the CAV's are derived from one or moreof the following acoustic values (which could also be internal hearinginstrument parameters):

-   -   signal level in 3 or more bands,    -   modulation index in 3 or more bands,    -   speech presence flag,    -   wind noise flag,    -   directional flag.

The above acoustic values are often already calculated because they areused in the signal processor for providing the best output and it doestherefore not cause any higher power consumption or the use of moreprocessing power to generate these acoustic values. Further thecombination of these values gives a very accurate description of thesound environment. Many other CAV values could be used, but not too manydifferent acoustic values should be used due to storage limitations. Notonly acoustic values belonging to the environment are usable hear. Alsoparameters belonging to the hearing aid could be used, such as thecurrent setting, battery power or other values regarding the hearingaid.

In an embodiment means are provided for storing of CAV's derived fromthe signal during use of each of the user chosen PPS's during a learningperiod in the manual mode whereby the means comprises a number ofstoring places preferably arranged as a second cyclic buffer in a secondmemory for each of the CAV's for storing consecutively derived values,and storing places in the second memory for storing the most frequentlyoccurring value in the cyclic buffer.

The CAV readings are bound to vary somewhat, even if the soundenvironment is quite stable and the value, which gets stored for furtheruse, must reflect several readings extending over some time. By usingthe most frequently occurring value it is assured, that the CAV valueswhich gets stored as a permanent signature for the environment carry themost information about the environment.

However in some cases this is not entirely true, because if thedifference between most frequently occurring value and second mostfrequently occurring value is small, it could indicate that thecharacterizing value does not carry significant information about thesound environment. Therefore the CAV's are stored along with a weightindicator. The weight indicator shows how much the corresponding storedCAV fluctuates in the cyclic buffer. If the CAV stays unchanged, theweight indicator is high to signify that this CAV is an important factorin the current environment, and if the CAV changes a lot, a low weightindicator gets assigned, to signify that this CAV value is notsignificant for the current environment.

In an embodiment of the hearing aid system the CAV values to be used inautomatic mode and manual mode comprises mean values derived by firststoring consecutive acoustic values calculated directly from the inputsignal of the hearing aid in a first cyclic buffer and storing the mostfrequently occurring values, such that the most frequently occurringvalue is the CAV used.

In this way transients, which may occur in the sound environment willnot get a dominating influence on the CAV values which are calculatedand further used by the hearing aid.

In a further embodiment of the hearing aid system according to theinvention, the first cyclic buffer has a first length and updatefrequency in the manual mode and a second length and update frequency inthe automatic mode. In this way this part of the system is shapeddynamically according to the specific task which is performed.

The cyclic buffer makes it possible to see if any of the characterizingvalues change more permanently to a new constant level, which could formthe basis of a new CAV set being written into the memory.

In a further embodiment of the hearing aid system a comparison and agrading means are provided for comparing the current CAV's stored in thefirst memory in automatic mode with the CAV's belonging to each PPS andstored in the second memory in manual mode and whereby a grade isassigned to each PPS for the correspondence between the current CAV andthe CAV belonging to the respective PPS whereby a further cyclic bufferis provided with places for each available PPS and arranged to receiveconsecutive grades and where the PPS having the highest average gradingover the cyclic buffer is used in the signal processing means.

Preferably the comparison between current and stored CAV's is carriedout with respect to the weight indicator stored along with the CAV'sduring the learning phase. If the stored CAV and the current CAV haveequal values the weight gets added to a sum, and sums for each PPS arecompared and a grading is assigned to each PPS according to the sum. Thegrades have two values, namely the value 1 for best correspondencebetween current and stored CAV and 0 for the remaining pairs of storedand current CAV's. This makes the averaging simple, as it is the PPS,which has the highest number of ones, which is being used. The length ofthe further cyclic buffer is preferably set to 61, but other values arepossible. The length-range should be from about 30 up to 200. Largerlength will give more precise decision; shorter length will give fasterswitching. With some intermediate values, e.g., 40, 61, 92, 150, atrade-off between switching-speed and decision-accuracy can be reached.61 is a good compromise and trials have shown well functioning hearingaids with this value.

According to yet another embodiment of the hearing aid system a furtheruser input means is provided for user determined selection of at leastone parameter value belonging to a PPS during use by the signalprocessing means in the manual or the automatic mode. Hereby it ispossible to give the user access to one or more specific parameters ofthe processing parameter set currently in use. In this way the user mayget the possibility to adjust the gain or any other parameter. This isan advantage, as it may occur that the automatically set gain in certaincircumstances could lead to uncomfortable sound levels or to too lowsound levels.

In an embodiment of the hearing aid system means are provided forcomparing the user determined parameter value with the value of thecorresponding parameter belonging to the stored PPS. Means are alsoprovided for changing the value of the parameter belonging to the storedPPS in order to reduce the difference between the value of the storedparameter and the value of the user determined parameter. In this way itis ensured that the user preference of e.g. gain setting is stored. Whenthis PPS is later chosen in either automatic or manual mode the usergain is set more accurately according to the user preference.

It is preferred that at least one user determinable parameter valuecomprises the gain setting. Other parameters could however also be usedfor this purpose.

The invention also comprises a method for choosing program in a multiprogram hearing aid as claimed in claims 10-19.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall diagram of the hearing aid.

FIG. 2 is a detailed diagram of the aid function in the learning mode,

FIG. 3 shows a detailed diagram of the hearing aid function in automaticmode,

FIG. 4 displays in part the contents of the second cyclic buffer in thesecond memory,

FIG. 5 shows in part the contents of the first cyclic buffer in thefirst memory in learning mode,

FIG. 6 shows in part the contents of the first cyclic buffer in thefirst memory in automatic mode,

FIG. 7 displays the comparison between current environment and thestored environment data of each PPS.

DESCRIPTION OF A PREFERRED EMBODIMENT

The hearing device in FIG. 1 has two microphones 1, a signal processingunit 2, and a receiver 3. The signal processing unit 2 provides anoutput signal to a receiver 3, which supplies an audio output to theuser of the hearing aid. The hearing aid has two different operationalmodes, namely a manual/learning mode and an automatic mode. In bothmanual mode and automatic mode acoustic values are calculated from theinput signal, stored in a cyclic buffer and from the cyclic buffer anaverage is extracted and stored for further use. This is illustrated byFIG. 4. The averaging which is proposed according to the current exampleof the invention is that the most frequently occurring acoustic valuesgets loaded into the memory for further use, but other averaging schemescould be used. FIGS. 5 and 6 shows an example of the content of thecyclic buffer with the acoustic values representing single pointmeasurements of the acoustic environment. The most frequent occurringvalue is stored and represents the Characterizing Acoustic Value or CAVwhich is used in the further calculations. In FIG. 5 the cyclic bufferhas a length of 5 and is used in the manual mode, and in FIG. 6 thebuffer has a length of 9 and this buffer length is used in automaticmode.

In FIG. 2 the utilities for the learning mode is displayed and in FIG. 3the utilities for the automatic mode is shown. The user decides byactivating user input means (not shown) whether learning or automaticmode is used in the hearing aid. Alternatively the hearing aid has atime function which activates the learning mode for a period of timefrom the date, when the user starts wearing the hearing aid, and thenautomatically switches to the automatic mode.

In the manual/learning mode the user has to choose the program, alsocalled processing parameter set (PPS), which provides the best signal,whereas in the automatic mode the hearing aid chooses the PPS to be usedin the signal processor 2. This automatic choice is based on the currentsound environment and the choices made by the user in the learning mode.This is further explained in the following.

In FIG. 2 the learning mode is displayed. In the learning mode the userchooses between a number of predefined PPS or processing parameter sets(PPS 1, PPS 2, PPS 3) in order to get the best signal processing in thecurrent situation. The different processing parameter sets define theworking of the hearing aid, which means that the audiometric data of theuser are incorporated into each PPS. In FIG. 2 three different PPSpossibilities are displayed, but the number of PPS is decided andprogrammed into the apparatus by the hearing aid acoustician before thehearing aid is handed over to the user. This number and the content ofeach of the PPS may vary according to the needs of the individual user.

In the described embodiment the acoustic values used can be describedusing 18 binary places, or 18 different acoustic values are used todescribe the environment. The 18 corresponding characterizing acousticvalues are taken from the storing places of the first memory 4 (FIG. 5,column 8), and so they each represent the sound environment over sometime. FIG. 5 shows how the acoustic values are stored in a buffer(column 2-6) of length 5. The majority value (column 8) of the buffer isused as the current CAV value, which are used in further calculations.

As seen in FIG. 4 the value 0 or 1 of each of the 18 places is loadedinto a cyclic buffer according to the chosen PPS. The buffer length ischosen to 16 in the described example, as seen in FIG. 4. For each ofthe 18 places or CAV values the number of ones is counted and stored.Column 7 in FIG. 4 holds the number of ones. If 8 or more 1's is countedthe value 1 is chosen as the best value for describing the soundenvironment, and if 0-7 ones is counted the value 0 gets stored as thebest describing value. If the number of 1's is close to 0 or close to 16for a given CAV the weight is high, which indicates that this particularCAV is significant. If the number of 1's is close to 8 for a given CAVthe weight (column 9) is low or even 0 to indicate that this CAVfluctuates and therefore is not an important parameter in the currentenvironment. The weight indicator is shown in the right column in FIG.4. This weight indicator could also be a value determined by informationtheory principles, in order to have biggest weight for most consistentinformation.

In the beginning the user may have to listen to the hearing aid witheach of the PPS possibilities turned on, in order to decide which one ispreferable in the current situation. Therefor the capture and storing ofenvironment data or characterizing acoustic values (CAV) is notcommenced before some time has lapsed without changes in the choice ofPPS. When the hearing aid is handed out to the user default CAVs arestored in the memory. The CAV are consecutively captured and storedaccording to the user chosen PPS in a second cyclic buffer of a secondmemory.

In the presented embodiment of the invention the second cyclic buffer inthe second memory for storing characterizing acoustic values derivedfrom the input signal has a length of 16. New CAV values get stored inthis buffer every 10 seconds. This is shown in FIG. 4 where the contentsof the cyclic buffer is shown at a given time.

FIG. 3 displays the working of the hearing aid in the automatic mode.Here current acoustic values are captured and loaded into the firstcyclic buffer. The buffer has a length of 9 and new acoustic values aregenerated and loaded into the buffer every 0.2 seconds. An example ofthe content at a given time is shown in FIG. 6. The content of thecyclic buffer is used to determine what the current auditory environmentis like and this is be done by the use of some kind of averagingfunction. In the present embodiment of the invention it is preferred touse that buffer value, which occurs most frequently for each of theacoustic values. These most frequent values get stored in a memory asthe Characterizing Acoustic Values of the current environment, and canthen be compared to the CAV, which have been assigned to each PPS duringthe learning period as explained above. The CAV values of the memorythen reflects the condition of the acoustic environment throughout thepast 2 seconds.

The task of comparing current and stored CAV's and choosing thebest-suited PPS for the current environment is handled as described inthe following with reference to FIG. 7. The current CAV is compared toeach of the stored CAV using the weight indicators. If bits are equal,it indicates that the current measured CAV parameter is the same as theCAV parameter found at listening to the corresponding PPS and thecorresponding weight gets added to a score assigned to that PPS. In FIG.7 the summation of the scores is in the bottom-most row. Not all of theCAV values are displayed, but only as examples No. 1-4 and 18 are shown.The PPS with the highest score wins. In the case displayed in FIG. 7 itis PPS 3 which has the highest score. A grade is assigned to each PPSaccording to how well the current CAV corresponds with the stored CAV.In the present realization of the invention there are two grades, namelyone for best match, and zero for all other matches. In the exampleaccording to FIG. 7, PPS 1 and 2 gets the grade 0 and PPS 3 getsassigned the grade 1. Consecutive grades get loaded into a cyclic bufferwith places for a number of grades for each PPS. That PPS which has thehighest number of ones in the cyclic buffer is chosen and used in theon-going signal processing of the hearing aid. The length of this cyclicbuffer is chosen to 61. However other lengths are possible.

As seen from the above, the determination of CAV belonging to aparticular PPS chosen by the user takes place in two steps: First theacoustic environment values are stored as they are captured, and themost frequently occurring value is used to give CAV values. The CAVvalues are logged over some time, and the most frequently occurringvalues are assigned to the particular PPS chosen by the user.

In each PPS a gain is specified, but the user may also be given controlof the gain through a further user input possibility. Through thispossibility the user may adjust the gain according to his or herpreference. Basically this has to be done at every shift of the PPS ifthe specified gain is not according to the users liking. In order toavoid this the hearing aid according to the invention monitors the userschanges of gain, and if the user chooses a gain setting which is higherthan the specified gain a new gain setting gets stored in the PPSmemory. The new gain is set one dB higher than the originally specifiedgain. This will happen each time this particular PPS is used and aftersome time the specified gain will be according to the users liking. Ifthe user at a later time changes his mind and whishes a lower gain, hejust chooses to set the gain lower each time the particular PPS is used,and after some time the initial gain setting of this PPS will reach alower value. This feature of the hearing aid according to the inventionis active both in the learning mode and in the automatic mode. In thepresent example the gain is the parameter, which the user may change,but other parameters may be changeable in this way like the cut-offfrequencies or time-constants (attack-, release-times).

1. A hearing device comprising: a programmable hearing aid having aninput transducer and an output transducer with a signal paththerebetween, signal processing means connected in said signal path forinfluencing a signal in the signal path dependent on a PPS or processingparameter set, and a PPS memory accessible by the signal processor meansfor storing a number of different PPS's for use by the signal processingmeans, user input means for the user to choose a specific PPS to be usedby the signal processing means in manual mode whenever the userexperiences a specific acoustic environment, means for capturing andstoring in a second memory of CAV's or characterizing acoustic valuesderived from the signal during use of each of the user chosen PPS duringa learning period in the manual mode whereby the means comprises anumber of storing places arranged as a second cyclic buffer in thesecond memory for each of the CAV's for storing consecutively derivedvalues, and storing places in the second memory for storing the mostfrequently occurring value of each CAV in the cyclic buffer, means forcapturing and temporarily storing in a first memory of current CAV in anautomatic mode, means for automatic selection of a PPS in an automaticmode, whereby the automatic selection is based on the comparison betweencurrent CAV's stored in the first memory and CAV's stored in the secondmemory.
 2. Hearing aid system as claimed in claim 1, whereby theacoustic values used to derive the CAV's comprises one or more of thefollowing: signal level in 3 or more bands, modulation index in 3 ormore bands, speech presence flag, wind noise flag, directional flag. 3.Hearing device as claimed in claim 2, whereby the hearing aid comprisesa first cyclic buffer for storing consecutive acoustic values calculateddirectly from the input signal, and means for selecting and storing themost frequently occurring values in the cyclic buffer as the CAV values.4. Hearing device as claimed in claim 3, whereby the first cyclic bufferhas a first length and update frequency in the manual mode and a secondlength and update frequency in the automatic mode.
 5. Hearing device asclaimed in claim 4, whereby a comparison and a grading means is providedfor comparing the current CAV's stored in the first memory in theautomatic mode with the CAV's belonging to each PPS and stored in thesecond memory in the manual mode and whereby a grade is assigned to eachPPS for the correspondence between the current CAV and the CAV belongingto the respective PPS whereby a further cyclic buffer is provided withplaces for each PPS and arranged to receive consecutive grades and wherethe PPS having the highest average grading over the cyclic buffer isused in the signal processing means.
 6. Hearing device as claimed inclaim 1 having second user input means for user determined selection ofat least one parameter value belonging to a PPS during use by the signalprocessing means in the manual or the automatic mode.
 7. Hearing deviceas claimed in claim 6 where means are provided for comparing the userdetermined parameter value with the value of the corresponding parameterbelonging to the stored PPS and where means are provided for changingthe value of the parameter belonging to the stored PPS in order tominimize the difference between the value of the stored parameter andthe value of the user determined parameter.
 8. Hearing device as claimedin claim 7, wherein the at least one determinable parameter valuecomprises the gain setting.
 9. Method for choosing program in a multiprogram hearing device, whereby the hearing device has an inputtransducer and an output transducer with a signal path there between,providing signal processing means connected in said signal path forinfluencing a signal in the signal path dependent on a PPS or processingparameter set, and providing a PPS memory accessible by the signalprocessor means and storing a number of different PPS's for use by thesignal processing means, providing user input means for the user tochoose a specific PPS to be used by the signal processing means wheneverthe user experiences an acoustic environment, capturing and storing in asecond memory of CAV's or characterizing acoustic values derived fromthe signal during use of each of the user chosen PPS during the learningperiod in the manual mode are stored in second cyclic buffer in thesecond memory and where the most frequently occurring value for each ofthe CAV's is stored in the second memory, capturing and temporarilystoring in a first memory of current, CAV's-automatic selection of aPPS, whereby the automatic selection is based on the comparison betweencurrent CAV stored in the first memory and CAV's stored in the secondmemory.
 10. Method for choosing a program as claimed in claim 9, wherebythe CAVS comprises one or more of the following: signal level in 3 ormore bands, modulation index in 3 or more hands, speech presence flag,wind noise flag, directional flag. 11-19. (canceled)
 20. Method forchoosing a program as claimed in claim 9, whereby the CAV values to bestored in the second cyclic buffer are derived by first storingconsecutive acoustic values calculated directly from the input signal ofthe hearing aid in a first cyclic buffer and storing the most frequentlyoccurring value, such that the most frequently occurring values are usedin the CAV values.
 21. Method as claimed in claim 20, whereby the firstcyclic buffer has a first length and update frequency in manual mode anda second length and update frequency in the automatic mode.
 22. Methodas claimed in claim 9, whereby the current CAV values which are storedin the first memory in the automatic mode are compared with the CAVvalues belonging to each PPS and stored in the second memory in themanual mode, and whereby a grade is assigned to each PPS for thecorrespondence between the current CAV and the CAV belonging to therespective PPS, whereby a further cyclic buffer is provided with placesfor each PPS and arranged to receive consecutive grades, and where thePPS having the highest average grading over the cyclic buffer is used inthe signal processing means.
 23. Method as claimed in claim 9, andwhereby second user input means are provided for user-determinedselection of at least one parameter value belonging to a PPS during useby the signal processing means in the manual or the automatic mode. 24.Method as claimed in claim 23, where the user-determined parameter valueis compared with the value of the corresponding parameter belonging tothe stored PPS and where the value of the parameter belonging to thestored PPS is changed in order to minimize the difference between thevalue of the stored parameter and the value of the user-determinedparameter.
 25. Method as claimed in claim 15, wherein the at least oneuser-determinable parameter value comprises the gain setting.